Structure and succession dynamics of a Neotropical freshwater periphyton community, with emphasis on ciliates and their association with bacterial taxa

Periphyton communities in freshwater systems play an essential role in biogeochemical processes, but knowledge of their structure and dynamics lags far behind other environments. We used eDNA metabarcoding of 16S and 18S rRNA markers to investigate the formation and establishment of a periphytic community, in addition to morphology-based analyses of its most abundant group (peritrich ciliates). We sampled two nearby sites within a large Neotropical lake at four time points, aiming to assess whether periphyton establishment can be replicated on this local scale. Producers and denitrifiers were abundant in the community, illustrating the relevant role of biofilms in freshwater nutrient recycling. Among microeukaryotes, peritrich ciliates dominated the community, with genera Epistylis and Vorticella being the most abundant and showing a clear succession at both sites. Other ciliates were identified and, in some cases, their occurrence was strongly related to bacterial abundance. The structure and succession dynamics of both prokaryotic and eukaryotic components of periphyton differed between the two sites, in spite of their adjacent locations and similar abiotic properties, indicating that the establishment of these communities can vary even on a local scale within a lake ecosystem.

Epiphytic microalgae community as aquatic bioindicator in Brantas River, East Java, Indonesia

Arsad S, Putra KT, Latifah N, Kadim MK, Musa M. 2021. Epiphytic microalgae community as aquatic bioindicator in Brantas River, East Java, Indonesia. Biodiversitas 22: 2961-2971. One way to monitor water quality is by using biological indicators, namely epiphytic microalgae (periphyton). This study aims to analyze the epiphytic periphyton community structure and analyze the river health status using a saprobic index. The research location was in the Brantas River, Blitar District, East Java, Indonesia. The method used was a survey with sampling at three sites based on the purposive sampling technique. Periphyton samples were taken using the quadrant transect (5x5 cm²) method and then identified using the Lackey Drop Micro transect Counting Method. The results show that the periphyton community structure is in balance, and there are six divisions of 59 different genera. The six divisions found are Bacillariophyta, Cyanophyta, Chlorophyta, Charophyta, Ochrophyta, and Rhodophyta. The most identified genus is from the Bacillariophyta Division with 28 genera, while the least identified genus is the Rhodophyta division with 1 genus. The abundance ??ranges from 242,800-1,229,174 cells. cm-2, the relative abundance index ??of periphyton ranges from 3-60% (site 1), 9-57% (site 2), 1-62% (site 3), the diversity index ranges from 1.212-2.617 (moderate), the uniformity index ranges from 0.307-2.151 (high), the dominance index ranges from 0.105-0.549 (moderate), and the saprobic index ranges from-0.18 to 0.55. Moreover, supporting water quality parameters are still optimal, except for ammonia and total organic matter parameters that exceed the quality standard. Based on the saprobic value obtained, the water quality of the Brantas River in Tawangrejo Village can be classified into the category of ?/?-mesosaprobic to ?-mesosaprobic saprobic levels with mild to moderate levels of pollution.

Changes of Periphyton Abundance and Biomass Driven by Factors Specific to Flooding Inflow in a River Inlet Area in Erhai Lake, China

Periphyton is an ecological essential in freshwater lakes and rivers. Its abundance and biomass are very dynamic in various habitats and subject to various factors, for example, nutrient and light. Following flooding events, the transitional area adjacent to a river inlet and the shallow lake generates diverse habitats for periphyton with gradients in current velocity, suspended matters, nutrients, and light, which would strongly shape the growth and community of periphyton. In this study, three sampling sites were established around a river inlet in Erhai Lake, China, and a field survey was conducted in the sites from April to August (flooding seasons) in 2019 to investigate the abundance and biomass of periphyton and explore influential factors. The results showed that three study areas have different gradients of current velocity depending on the distance to the river inlet, thereby regulating the concentrations of nutrients and suspended matters, which strongly affected the periphyton community; to be specific, the biomass of periphyton was inhibited by the concentration of suspended matters and high concentrations of silicate mainly reduced the diversity of periphyton. Our results imply that the study on the driving factors of periphyton could help to understand its community assembly mechanism and biomass and species composition of periphyton can provide some reference for trophic state of the lake.

Changing Water Levels in Lake Superior, MI (USA) Impact Periphytic Diatom Assemblages in the Keweenaw Peninsula

Predicted climate-induced changes in the Great Lakes include increased variability in water levels, which may shift periphyton habitat. Our goal was to determine the impacts of water level changes in Lake Superior on the periphyton community assemblages in the Keweenaw Peninsula with different surface geology. At three sites, we identified periphyton assemblages as a function of depth, determined surface area of periphyton habitat using high resolution bathymetry, and estimated the impact of water level changes in Lake Superior on periphyton habitat. Our results suggest that substrate geology influences periphyton community assemblages in the Keweenaw Peninsula. Using predicted changes in water levels, we found that a decrease in levels of 0.63 m resulted in a loss of available surface area for periphyton habitat by 600 to 3000 m2 per 100 m of shoreline with slopes ranging 2 to 9°. If water levels rise, the surface area of substrate will increase by 150 to 370 m2 per 100 m of shoreline, as the slopes above the lake levels are steeper (8–20°). Since periphyton communities vary per site, changes in the surface area of the substrate will likely result in a shift in species composition, which could alter the structure of aquatic food webs and ecological processes.

STUDI KEANEKARAGAMAN DAN STRUKTUR KOMUNITAS PERIFITON DI PERAIRAN SUNGAI COBAN RONDO MALANG

Periphyton is a community of microorganisms that live attached to or adjacent to a substrate sink. For aquatic organisms, periphyton habitats have a relatively fixed. With it is so, the changes of water quality and substrate greatly affects the composition of his life and abundance. Periphyton composition and abundance depends on the tolerance or sensitivity to environmental changes. This study aims to determine each periphyton community in responding to changes in habitat quality by way of adjustment in community structure. The methodology used in this prektikum involves taking data from four stations along the river Coban Rondo, in each station there are 3 replicates. And take measurements of factors such environments as supportive data turbidity, flow rate, pH, and depth. Analyzed using Simpson's Dominance Index to determine the type of periphyton dominance, as well as morisita similarity indices and cluster analysis. The results showed that the diversity in each station belonging to the category of high (H more than 3.32) because the obtained value of the index H' between 3.2 to 3.48. Species that dominate from the four stations is Pinularia with an average Index Value Important (IVI) 31,5.

Perifiton Community Structure in Citarik River

The purpose of this research is to determine the condition of waters in the Citarik River with the periphyton community as a bio indicator. This research was conducted from March-April 2019. The research method used was a survey method at 4 station points, five times sampling with a span of 7 days. The smallest periphyton abundance is in station IV which is 22 ind/cm2 and the most is in station I which is 18278 ind/cm2. Comparison of species deficit values at each station is different, this is influenced by different physical and chemical parameters. The dominance index value in the waters of the Citarik River ranges from 0.1 to 0.8 and the diversity index value ranges from 0.2 to 0.9. The results showed the Citarik River was in a mildly polluted condition.

Biological method in monitoring small rivers of the Oka River basin

The Oka basin is characterized by serious environmental problems associated with the depletion of water resources. Communities of aquatic organisms are the first to respond to negative changes in the aquatic environment, such communities are used as indicators in biological monitoring. The aim of the work was to assess the ecological state of the small river of the Oka basin by bioindication. The quality of the water in the reservoir was assessed by chemical indicators - biogenic and technogenic elements. The saprobity index of the reservoir was determined by the species diversity of periphyton. The results revealed technogenic and organic pollution of the small river. According to the results of biological monitoring, the value of the saprobity index is 2.85, which corresponds to class 4 of the reservoir quality, and the water is assessed as polluted. Monitoring the degree of pollution of the small river by the biodiversity of the periphyton community allows you to determine the degree of water pollution quickly.